Context. The JAXA Hayabusa2 mission returned well-preserved samples collected from the carbonaceous asteroid Ryugu, providing unique non-terrestrially weathered samples from a known parent body. Aims. This work aims to provide a better understanding of the formation and evolution of primitive asteroidal matter by studying the fine scale association of organic matter and minerals in Ryugu samples. We characterized the samples by IR nanospectroscopy using infrared photothermal nanospectroscopy (AFM-IR) technique. This technique overcomes the diffraction limit (of several microns) of conventional infrared microspectroscopy (mu -FTIR). The samples were mapped in the mid-IR range at a lateral spatial resolution about a hundred times better than with mu -FTIR. This provided us with unique in situ access to the distribution of the different infrared signatures of organic components at the sub-micron scale present in the Ryugu whole-rock samples as well as to the characterization of the compositional variability of Ryugu in the insoluble organic matter (IOM) chemically extracted from the Ryugu samples. Methods. The AFM-IR maps of whole-rock particles and IOM residues from Ryugu samples were recorded with a lateral resolution of tens of nanometers. Spectra were recorded in the 1900-900 cm(-1) spectral range by AFM-IR (Icon-IR) for all samples, and additional spectra were recorded from 2700 to 4000 cm(-1) for one IOM sample by an optical photothermal IR (O-PTIR) technique using a mIRage (R) IR microscope. Results. Organic matter is present in two forms in the whole-rock samples: as a diffuse phase intermixed with the phyllosilicate matrix and as individual organic nanoparticles. We identify the Ryugu organic nanoparticles as nanoglobule-like inclusions texturally resembling nanoglobules present in primitive meteorites. Using AFM-IR, we record for the first time the infrared spectra of Ryugu organic nanoparticles that clearly show enhanced carbonyl (C=O) and CH contributions with respect to the diffuse organic matter in Ryugu whole-rock and IOM residue.

The extent and ecological significance of intraspecific functional diversity within marine microbial populations is still poorly understood, and it remains unclear if such strain-level microdiversity will affect fitness and persistence in a rapidly changing ocean environment. In this study, we cultured 11 sympatric strains of the ubiquitous marine picocyanobacterium Synechococcus isolated from a Narragansett Bay (RI) phytoplank-ton community thermal selection experiment. Thermal performance curves revealed selection at cool and warm temperatures had subdivided the initial population into thermotypes with pronounced differences in maximum growth temperatures. Curiously, the genomes of all 11 isolates were almost identical (average nucleotide identities of >99.99%, with >99% of the genome aligning) and no differences in gene content or sin-gle nucleotide variants were associated with either cool or warm temperature phenotypes. Despite a very high level of genomic similarity, sequenced epigenomes for two strains showed differences in methylation on genes associated with photosynthesis. These corresponded to measured differences in photophysiology, suggesting a potential pathway for future mechanistic research into thermal microdiversity. Our study demonstrates that present-day marine microbial populations can harbor cryptic but environmentally relevant thermotypes which may increase their resilience to future rising temperatures.

Hydropower and irrigation are essential for achieving human development objectives and for climate mitigation and adaptation. These sectors depend on the same grey infrastructure, such as dammed reservoirs, which has created negative socio-ecological externalities and sectoral conflicts in the past. Yet, future needs for infrastructure in both sectors and their interdependencies remain unclear. We address this gap by applying datafusion and machine-learning approaches and provide a comprehensive global overview and a new dataset that elucidates the role of existing dams and reservoirs for hydropower and irrigation. We then review projected demands for irrigation storage and hydropower by 2050 and analyze how projected growth aligns with the identified potential for irrigation and hydropower dams. Globally, projections point to an increased demand for hydropower in the order of 400 GW by 2050, which amounts to around 60 % -64 % of the identified potential and around +35 % compared to today. For irrigation, fully leveraging sustainable water resources would require 460 km 3 /yr of stored water, or around +70 % compared to today. Projected demands for hydropower and irrigation are larger than what future grey infrastructure could provide in many regions, especially in Europe, South Asia, and Africa. In such conditions, both sectors will be increasingly in competition for infrastructure. Our findings also highlight the need to study alternative solutions, such as other forms of renewable energy and nature-based solutions for water storage, to meet societal demands while avoiding negative externalities associated with grey water infrastructure.

Around 100 GW of new hydropower projects have been proposed in continental Africa to contribute to meeting future energy demand. Yet, the future expansion of hydropower on the continent faces obstacles due to the impacts of dams on rivers, greenhouse gas emissions from reservoirs and increasingly competitive alternative renewable electricity technologies. Here we propose an integrated approach to include these considerations in energy planning. Compared with planning for least-cost energy systems, capacity expansion strategies balancing environmental and techno-economic objectives increase electricity prices and total discounted costs by at most 1.4% and 0.2%, respectively, while reducing impacts on annual hydropower emissions and river fragmentation by at least 50%. Our results demonstrate that refining techno-economic analysis in light of global and local environmental objectives can help policymakers reduce the river fragmentation and greenhouse gas emissions associated with hydropower development at marginal increases in energy costs.

The development of modern large-scale spectroscopic survey telescopes responds to the urgent demand for spectral information in astronomical research. Tsinghua University has previously proposed a 6.5 m MUltiplexed Survey Telescope consisting of a Ritchey-Chretien configuration and a 1.8 m multi-element wide-field corrector, achieving excellent performance and world-leading survey efficiency. However, an optimized 1.65 m multi-element corrector with five lenses is proposed to overcome the constraints on glass uniformity and verification in fabrication of the previous corrector design. It maintains outstanding image quality, with the 80% enclosed energy diameter not more than 0.559 arcsec within 3 degrees FoV over up to a 55 degrees zenith angle. The optimized optical system does not revise the working mode of the ADC or the curvature of the primary mirror while ensuring the reasonability and accuracy of manufacturing of large corrector elements. It provides a more feasible reference optical design for the MUltiplexed Survey Telescope in subsequent iterations and communications with manufacturers.

Most plant genomes and their regulation remain unknown. We used SPLASH - a new, reference-genome free sequence variation detection algorithm - to analyze transcriptional and post-transcriptional regulation from RNA-seq data. We discovered differential homolog expression during maize pollen development, and imbibition-dependent cryptic splicing in Arabidopsis seeds. SPLASH enables discovery of novel regulatory mechanisms, including differential regulation of genes from hybrid parental haplotypes, without the use of alignment to a reference genome.

The structure of communities is influenced by many ecological and evolutionary processes, but the way these manifest in classic biodiversity patterns often remains unclear. Here we aim to distinguish the ecological footprint of selection-through competition or environmental filtering-from that of neutral processes that are invariant to species identity. We build on existing Massive Eco-evolutionary Synthesis Simulations (MESS), which uses information from three biodiversity axes-species abundances, genetic diversity, and trait variation-to distinguish between mechanistic processes. To correctly detect and characterise competition, we add a new and more realistic form of competition that explicitly compares the traits of each pair of individuals. Our results are qualitatively different to those of previous work in which competition is based on the distance of each individual's trait to the community mean. We find that our new form of competition is easier to identify in empirical data compared to the alternatives. This is especially true when trait data are available and used in the inference procedure. Our findings hint that signatures in empirical data previously attributed to neutrality may in fact be the result of pairwise-acting selective forces. We conclude that gathering more different types of data, together with more advanced mechanistic models and inference as done here, could be the key to unravelling the mechanisms of community assembly and question the relative roles of neutral and selective processes.

Plants have a protective mechanism called non-photochemical quenching to prevent damage caused by excessive sunlight. A critical component of this mechanism is energy-dependent quenching (qE). In Chlamydomonas reinhardtii, the protein expression called light-harvesting complex stress-related protein 3 (LHCSR3) is crucial for the qE mechanism. LHCSR3 expression is observed in various conditions that result in photooxidation, such as exposure to high light or nutrient deprivation, where the amount of captured light surpasses the maximum photosynthetic capacity. Although the role of LHCSR3 has been extensively studied under high light (HL) conditions, its function during nutrient starvation remains unclear. In this study, we demonstrate that LHCSR3 expression can occur under light intensities below saturation without triggering qE, particularly when nutrients are limited. To investigate this, we cultivated C. reinhardtii cells under osmotic stress, which replicates conditions of nutrient scarcity. Furthermore, we examined the photosynthetic membrane complexes of wild-type (WT) and npq4 mutant strains grown under osmotic stress. Our analysis revealed that LHCSR3 expression might modify the interaction between the photosystem II core and its peripheral light-harvesting complex II antennae. This alteration could potentially impede the transfer of excitation energy from the antenna to the reaction center.

Cell polarity is used to guide asymmetric divisions and create morphologically diverse cells. We find that two oppositely oriented cortical polarity domains present during the asymmetric divisions in the Arabidopsis stomatal lineage are reconfigured into polar domains marking ventral (pore -forming) and outward -facing domains of maturing stomatal guard cells. Proteins that define these opposing polarity domains were used as baits in miniTurboID-based proximity labeling. Among differentially enriched proteins, we find kinases, putative microtubule-interacting proteins, and polar SOSEKIs with their effector ANGUSTIFOLIA. Using AI -facilitated protein structure prediction models, we identify potential protein -protein interaction interfaces among them. Functional and localization analyses of the polarity protein OPL2 and its putative interaction partners suggest a positive interaction with mitotic microtubules and a role in cytokinesis. This combination of proteomics and structural modeling with live -cell imaging provides insights into how polarity is rewired in different cell types and cell -cycle stages.